Removable thread guide which receives threads projected onto a surface

ABSTRACT

The apparatus for the manufacture of a reinforcement from a thread deposited directly in its final position by projecting lengths of the thread for laying the thread onto a receiving surface (S). The apparatus includes an assembly (5) comprising rollers (15) for the advancing of thread (1), a rotary conduit (2), a knife (3) for cutting the thread and freeing a length (10) upon each turn of said rotary conduit (2), and a thread guide (4) to receive the cut lengths of thread. The thread guide comprises deflectors (43) exerting a pressure on the thread. The pressure of the deflectors can be adjusted by screws (7).

This convention application is also entitled to the priority of U.S.provisional application, Ser. No. 60/032,900, filed Dec. 16, 1996.

BACKGROUND OF THE INVENTION

The present invention relates, in particular, to the manufacture oftires, and more particularly, to the manufacture of reinforcementarmatures, such as those which are present below the tread of beltedtires, the carcass of which is generally radial.

Such reinforcements have been manufactured in the form of semi-finishedproducts known as "plies" which were prepared flat and then incorporatedin the assembling of the article. U.S. Pat. No. 4,952,259 relates to theproducing of such reinforcements from a continuous thread and placingthem directly on the tire blank. This proposal is based on theprojecting of a thread in the manner of the thong of a whip.

FIG. 1 illustrates an apparatus for the manufacture of a tirereinforcement employing this principle. Such an apparatus uses a thread1 fed, for example, by feeding means from a spool, not shown. Theapparatus projects lengths 10 of said thread onto a receiving surface Swhich in this case is part of the tire being manufactured.

The expression "thread" is used herein in a very broad sense to includea monofilament, a multifilament, a cable, a twist or an equivalentassembly, and this whatever the material constituting the thread or thetreatment which it has undergone, for instance a surface treatment inorder to favor its intimate bonding to rubber, or a rubberizingtreatment surrounding said thread with a layer of rubber in order topermit its direct adherence on the support upon its projection.

The apparatus is an assembly 5 which includes:

means for advancing the thread 1 from a source of thread (not shown),such as a spool,

a rotary conduit 2 mounted on a shaft 20 constituting the axis ofrotation of said conduit, in such a manner that the outer radial end 21of said conduit is directed substantially radially with respect to theaxis of rotation, said conduit receiving the thread 1 at its central end22 opposite said outer radial end 21 coming from the thread feedingmeans, said thread emerging through said outer radial end, said feedingmeans controlling the linear speed of advance of the thread within saidrotary conduit,

means for driving said rotary conduit 2 in rotation,

means for cutting the thread in such a manner as to free one length uponeach rotation of said rotary conduit 2.

Furthermore, said apparatus comprises a thread guide, designatedgenerally as 4, for receiving lengths 10 of thread. For further detailsas to the operation of an apparatus of this type, reference should bemade to U.S. Pat. No. 4,952,259. In that apparatus, the thread guide 4is positioned with respect to said rotary conduit 2 in such a manner asto receive the thread, or more precisely lengths 10 removed one afteranother from this thread, in the plane of rotation of said conduit 2.The thread guide 4 receives each length 10 of thread, which passesthrough this thread guide and emerges through a projection orifice 40 inthe immediate vicinity of the surface on which the length of thread isto be deposited and held by adherence. In a preferred embodiment of theapparatus, the lengths of cords are whipped and forced through thethread guide.

SUMMARY OF THE INVENTION

The object of the present invention is to simplify the production ofsuch a thread guide and to facilitate the use of such a thread-layingapparatus for a wide range of manufactured articles, for example for arange of tires of many different types, involving different dimensionsof crown reinforcements, curved to a greater or lesser extent on thesurface onto which the lengths of thread are projected, and alsodifferent types of threads.

According to the invention, the thread guide comprises a pair ofdeflectors, defining at least one elongated inner passage, placed insaid plane of rotation, the deflectors being arranged in such a manneras to leave between them a slot into which each length of thread canpass, said deflectors being arranged to exert a pressure towards eachother during passage of a length of cord through the slot, and on theprojection-orifice side, said deflectors being able to move apart forthe passage of a length of thread. The thread guide provides means forregulating the position of said deflectors relative to each other inorder to control the braking effect which they exert on threads toinsure proper placement of the threads on the surface.

The thread guide of the invention is more particularly advantageous whencertain metal reinforcement threads (wires) are deposited. In this case,it is desirable to brake the advance of the length of thread rathersubstantially before it reaches the surface of the tire blank in thecourse of manufacture. The amount of this braking depends on severalparameters, such as the nature of the wire and the nature of the rubbercoating covering the surface onto which the lengths of thread areprojected. The existence of means for adjusting the pressure makes itpossible to adjust the braking in the best possible manner and makes itpossible to facilitate the use of this type of apparatus and improve thereliability thereof.

In the following, the invention is illustrated by a particularembodiment in which the thread guide forms a removable subassembly whichcomprises a cradle. In this example, the cradle forms an elongated,closed rectangle formed by two parallel branches connected to each otherat their ends by braces and deflectors mounted within said branches. Thecradle is provided with a fastening surface which permits the threadguide to be detachably mounted to the assembly. The fastening surface ispreferably a simple, localized mounting for the thread guide, in thisexample, a mounting lug arranged on one of said branches on the sideopposite one of said deflectors.

This embodiment, which of course is not limitative, makes it possible topreadjust the thread guide while it is not yet mounted on thereinforcement manufacturing machine. In tire manufacturing shops, onecan have as many thread guides as necessary. When it is necessary toeffect the production of several different ranges of tires, requiring inpractice different adjustments of the thread guide, it is possible toselect among several thread guides which have been pre-adjusted in theshop. One has all the time necessary in order properly to adjust thedeflectors. This subassembly can then be mounted very rapidly on themachine at the desired moment, so as not to interfere with theproductivity of the machines.

All details of the invention are explained below, with the aid of theaccompanying drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the thread guide of the invention;

FIG. 2 is another view, showing part of the thread guide;

FIGS. 3 and 4 show, in greater detail, variant embodiments of anadjustment in accordance with the invention, in a half view and partialsemi-section along the line XX of FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows the assembly 5, the function of which is to deliver lengthsof thread provided with the movement which makes it possible for them tobe placed on the surface on which it is desired to deposit them. Thethread 1 is gripped between and advanced by feed rollers 15, one ofwhich is driven in rotation by the motor 16. A motor 25 drives the shaft20 through a belt 26. A stationary knife 3, arranged in the path of thethread 1 just downstream of the outer radial end 21, cuts the threadupon each revolution of the rotary conduit 2.

In the embodiment of the invention, the thread guide 4 forms a compactsubassembly which rests on the frame of the thread-laying apparatusproper. It is mounted to it in a very firm but removable manner and istherefore easily detachable. As a result, it is very simple to changethe thread guide when desired. One can make as many thread guides asnecessary, for instance as many as there are different curvaturespresented by the surface onto which the lengths 10 of thread areprojected. It is therefore no longer necessary to provide a mechanismfor adjusting the curvature. If it is necessary to use a differentconfiguration for the thread guide, this is done very simply by changingthe thread guide itself. Several pre-configured thread guides can bestored, so that this change can be carried out very rapidly.

It is important to note that, as compared with all the embodimentsdescribed in U.S. Pat. No. 4,952,259 mentioned above, the components ofthe assembly 5 are arranged in such a manner that all the mechanicalparts of the assembly 5 are grouped on a single side of the rotaryconduit 2. Stated differently, the drive of the rotation of said conduitand the drive of the thread 1 by the rollers are located on the sameside. This is made possible by offsetting the motor 25 with respect tothe shaft 20. This makes the mechanical structure very compact andfacilitates the design of a single fastening surface 42 of smalldimensions as compared with the space taken up by the thread guide 4.

It is seen that the thread guide 4 is mounted overhung on the frame ofthe assembly 5 containing the rotary conduit 2. The fastening surface 42is located at the interface between the thread guide 4 and the assembly5 (see FIG. 2). Said surface is continuous and is entirely circumscribedby a closed line 48 (FIG. 1). It is designed to permit the removablefastening of the said thread guide 4 on said assembly 5. For this, onecan use a quick-attachment system or even, very simply, screws 45. Asthe thread guide plays a guiding and braking role in order to assurehigh precision in the depositing of the lengths 10 of thread, it isimportant that the fastening surface 42 and the fastening meansselected, in this case screws 45, permit a sufficiently firm mounting.

The thread guide 4 comprises a cradle, designated generally as 41, forthe support of all the parts which constitute the thread guide. Thiscradle 41 includes a pair of deflectors 43 defining an elongated innerpassage containing said plane of rotation. The deflectors are eachformed by a metal sheet 430 fastened on a more solid support 431, in thepart of said sheet remote from the projection orifice, by upperfastenings 432 (see FIGS. 1 and 3). These upper fastenings 432 aredesigned to support each sheet 430 from its respective support 431. Thesupport 431 is either part of the cradle or attached to the inside ofit. As can be seen from FIGS. 3 and 4, the metal sheet 430 protrudesradially towards the projection orifice 40 beyond the support 431. Thismakes it possible to assure a certain possible elastic deformation ofthe deflectors in the transverse direction, even if the metal sheets areapplied against the support on the projection-orifice side.

Pressure screws 7 are arranged between metal sheet 430 and support 431to engage at least on one (FIG. 3) of said sheets in the region of thesheet closer to the projection orifice than the upper fastenings 432.Preferably, such pressure screws are installed to press against the twosheets and deflect them to control the width of the slot and the brakingaction which the sheets exert on the threads (FIG. 4). These screws 7make it possible to move the sheet 430 away from its support 431. Morespecifically, the screws deflect the sheets 430 toward each other withor without (depending on thread to be placed on the surface S) causingthe deflectors to make pressure contact with each other after adjustmentand at rest. During operation of the thread guide, the sheets wouldalways be spaced apart at the discharge of the threads from the threadguide onto the surface S. In one embodiment, the sheets are held apartfrom their respective supports until the two sheets 430 come intocontact with each other at least at a point or at points in the slot forthe passage of lengths of thread. The sheets are arranged in such amanner as to assure this contact at least on the side opposite therotary conduit 2, that is to say in the region of the thread guidefurthest from the assembly 5. It will be noted that the support 431 isprovided with several threaded holes 70 which serve as anchoring pointsfor the introductions of such pressure screws at the same level as thoseshown in the figures. There will also be noted the presence of otherthreaded holes 71 which can serve as possible anchoring points for theintroduction of such pressure screws at an intermediate level betweenthe pressure screws shown and the upper fastenings 432. It is possibleto use only some of these threaded holes 70 or 71, selected specificallyin accordance with the result of experimental tests carried out for eachof the types of thread to be projected. It will be recalled that thesepressure screws have been located in such a manner that, at the level ofthe lower edge 44, they permit the relative moving apart of said sheetsin order to permit the lengths of thread to pass, while assuring anelastic return towards the initial position. The adjustment of thesepressure screws 7 may be effected in the shop, off the machine,respecting pre-established directions as to prestressing.

FIG. 4 also shows another variant embodiment for the exerting of acertain pressure for the relative movement together of the sheets 430.The screws 7 act on the sheet 430 via a ring-shaped arc 72 (and possiblyseveral contiguous arcs) and a cushion 73 of rubber or any otherflexible material.

In the embodiment of the invention shown, the cradle 41 is formed by twocurved bars 46, by each of the solid supports 431, and by three braces47A, 47B and 47C. Seen in the plane of projection of the lengths, thecradle 41 has substantially the shape of a curved, closed, elongatedrectangle formed by two substantially parallel branches connectedtogether at their ends. The closed structure of the cradle 41 imparts toit strength, rigidity and lightweight, features which, in addition tothe use of a fastening surface 42 of fixed location, insure that thecradle is easy to remove and replace. Note that the cradle can becomeclosed through the fastening means at the time it is attached to theassembly 5, and this variation is within the meaning of the term"closed" as used herein. The deflectors are mounted within saidbranches, and the fastening surface is arranged on one of said brancheson the side opposite one of said deflectors. The deflectors are shapedin such a manner that the distance between each deflector decreases asthe projection orifice is approached (see FIG. 2).

The rectangle which the cradle 41 forms leaves a sufficiently longpassage so that the lengths 10 can pass through. The brace 47C does notinterfere with the passing of the length 10 which has just been freed bythe knife 3, nor with the passing of the end of the thread which emergesfrom the outer radial end 21 of the rotary conduit 2. The feed of thethread imparts to it a continuous advance, and just after the cutting bythe knife 3, the end of the thread (the length is not designated here)forms a spiral path in the plane of rotation of the conduit 2. The brace47C must therefore be located radially beyond this path in order not tointerfere with the movement of the thread.

Furthermore, in order to provide another means of adjusting the pressureof the deflectors towards each other, at least one of said braces(preferably the brace 47B) is of variable length in order to adjust thedistance between said deflectors. Preferably all the braces 47A, 47B,and 47C are adjustable: they have a threaded rod which is fastenedimmovably on one of the supports 431 and maintain the other support 431by means of nuts and lock nuts. This type of adjustment can be usedsimultaneously with the adjustment described above, or each of theadjustments can be used alone. If one designs a thread guide for asingle specific thread, one can also use spacing inserts to hold in anunadjustable manner the sheets at a given distance remote from thesupport.

The deflectors are arranged in such a manner as to leave between them aslit through which each length of thread can pass forcibly. Eachdeflector comprises, on the projection-orifice side, an edge 44 which iscurved in such a manner as to approach the shape of the receivingsurface S onto which the lengths 10 of thread are projected. This edge44 corresponds to the lower edge of the corresponding metal sheet 430.In this example, the edge closely follows the curve of the crown of atire, as viewed in planar radial section, and forming a typical angle ofthe crown reinforcement threads. More generally, the trace which theperpendicular projection of each of said edges forms in the plane ofrotation of the rotary conduit 2 is non-linear in order to follow moreor less closely the curves of the receiving surface.

The dimensions of the fastening surface 42 are substantially smallerthan the length of the deflectors measured along said edge 44, that isto say along the slit through which the lengths 10 pass.

The clearance between the edges 44 and the receiving surface S issubstantially constant (see FIG. 1). It corresponds, for instance, totwo or three times the thickness of a length 10 of thread. Due to thefact that the metal sheet 430 makes it possible to assure a continuousguiding of the length 10 along its entire length, a precise depositingof the length at the desired place is obtained. In practice, it is onlythe metal sheets 430 which must be cut to the approximate profile of thesurface S. Furthermore the rubbing of the lengths 10 on these sheetscauses in the long run a certain amount of wear of the sheets. For allof these reasons, it is very practical to be able to replace them.However, in order not to reduce the productivity of the machines, theinvention makes it possible to replace the metal sheets on a threadguide which is not mounted on the assembly 5. One thus works on asubassembly (thread guide 4) in the shop, having all the time necessaryin order properly to mount and adjust these sheets 430 correctly,whereupon this subassembly can be mounted on the machine at the desiredtime.

The cradle 41 thus constitutes a mechanical support on which all of theparts of the thread guide are combined. Furthermore, it is known thatthe rotary conduit and the driving members for the thread form anassembly 5 which must approach the surface on which it is desired tomanufacture a crown reinforcement and correctly position it in order forthe threads to be projected precisely at the desired place. The same istrue with respect to the thread guide. Since the cradle 41 is integralwith said assembly 5, it will be understood that the thread guide 4precisely follows the movements which a mechanism (not shown) may conferupon the assembly 5 in order to enable it to approach the support onwhich a tire is manufactured.

I claim:
 1. An apparatus for manufacturing a reinforcement from a threaddeposited directly at its final place by projecting lengths of saidthread onto a receiving surface, said apparatus including an assemblycomprising:means for advancing the thread, a rotary conduit fastened ona shaft constituting the axis of rotation of said conduit, so that theouter radial end of said conduit is oriented substantially radially withrespect to the axis of rotation, said conduit receiving the thread fromthe advancing means at its central, inner end opposite said outer radialend, said thread emerging through said outer radial end, said advancingmeans controlling the linear speed of advance of the thread within saidrotary conduit, means for driving said rotary conduit in rotation, meansfor cutting the thread to free a length upon each rotation of saidrotary conduit,said apparatus further comprising a thread guide forreceiving lengths of thread, the thread guide being positioned withrespect to said rotary conduit in such a manner as to receive the threadin the plane of rotation of said conduit, said thread guide having aprojection orifice from which the thread can emerge,in which the threadguide comprises a support and a pair of deflectors mounted on thesupport at a part of the deflector which is remote from the projectionorifice, said pair of deflectors defining between them at least oneelongated inner passage located in said plane of rotation, said threadguide further comprising means for adjusting the spacing between thesupport and a side of at least one deflector in the region of thedeflector remote from the projection orifice and remote from saidmounted part of the deflector, thereby adjusting the relative positionsof the deflectors to control the pressure which the deflectors exert onthe passage of lengths of thread before their discharge from theprojection-orifice of the thread guide, which deflectors are capable ofbeing deflected away from each other by the passage of a length ofthread between them at the discharge from the projection orifice.
 2. Anapparatus according to claim 1, developed for the production in situ ofa tire reinforcement during its manufacture, in which each deflectorcomprises on the projection-orifice side an edge which is curved in sucha manner as to approach the shape of said receiving surface.
 3. Anapparatus according to claim 1, in which the thread guide comprises acradle forming an elongated mounting structure for the deflectors, saidstructure being defined by two parallel branches connected together attheir ends by braces, the parallel branches and end braces defining aclosed, elongated rectangle when viewed from above, said deflectorsbeing mounted within said branches, at least one of said braces being ofvariable length so as to adjust the distance between said deflectors. 4.An apparatus according to claim 1, in which each of the deflectorscomprises a single sheet.
 5. An apparatus according to claim 4, in whichthe means for adjusting the spacing between the support and a side of atleast one of the deflectors is a pressure screw arranged between atleast one metal sheet and the support in order to engage the sheetintermediate the mounted part and the projection orifice.
 6. Anapparatus according to claim 5, in which the pressure screw is arrangedto engage the side of the sheet opposite the side which defines theinner passage for the thread.
 7. An apparatus according to claim 1, inwhich the distance between the deflectors decreases upon approaching theprojection orifice.
 8. An apparatus according to claim 3, in which saidthread guide is a removable subassembly and in which the cradle isprovided with a fastening surface which permits the removable fasteningof said thread guide to said assembly, the surface being arranged on oneof said branches on the side opposite one of said deflectors.
 9. Anapparatus according to claim 8, in which said fastening surface is ofsubstantially smaller dimensions than the length of the deflectorsmeasured along said elongated passage.
 10. An apparatus according toclaim 8, in which said fastening surface is continuous and entirelycircumscribed by a closed line.
 11. An apparatus according to claim 1,in which the thread guide is a unitary subassembly removably mounted tothe apparatus to facilitate removal as a unit and substitution ofanother thread guide.
 12. An apparatus according to claim 1, in whicheach deflector comprises on the projection-orifice side an edge and inwhich the trace which the perpendicular projection of each of said edgesforms in the plane of rotation is non-linear.
 13. An apparatus accordingto claim 1, in which the deflectors are in contact with each other atleast at a point or points in the elongated passage.
 14. An apparatusfor manufacturing a reinforcement from a thread deposited directly atits final place by projecting lengths of said thread onto a receivingsurface, said apparatus including an assembly comprising:means foradvancing the thread, a rotary conduit fastened on a shaft constitutingthe axis of rotation of said conduit, so that the outer radial end ofsaid conduit is oriented substantially radially with respect to the axisof rotation, said conduit receiving the thread from the advancing meansat its central, inner end opposite said outer radial end, said threademerging through said outer radial end, said advancing means controllingthe linear speed of advance of the thread within said rotary conduit,means for driving said rotary conduit in rotation, means for cutting thethread to free a length upon each rotation of said rotary conduit,saidapparatus further comprising a thread guide for receiving lengths ofthread, the thread guide being positioned with respect to said rotaryconduit in such a manner as to receive the thread in the plane ofrotation of said conduit, said thread guide having a projection orificefrom which the thread can emerge,in which the thread guide comprises apair of deflectors defining between them at least one elongated innerpassage located in said plane of rotation and a cradle forming anelongated mounting structure for the deflectors, said structure beingdefined by two parallel branches connected together at their ends bybraces, the parallel branches and braces defining a closed elongatedrectangle when viewed from above, said deflectors being mounted withinsaid branches, at least one of said braces being of variable length soas to adjust the distance between said deflectors, thereby adjusting therelative positions of the deflectors to control the pressure which thedeflectors exert on the passage of lengths of thread before theirdischarge from the projection orifice of the thread guide, whichdeflectors are capable of being deflected away from each other by thepassage of a length of thread between them at the discharge from theprojection orifice.
 15. An apparatus according to claim 14 in which eachof the deflectors comprises a single metal sheet mounted on a support ofthe mounting structure at a part of said sheet remote from theprojection orifice.
 16. An apparatus according to claim 14 developed forthe production in situ of a tire reinforcement during its manufacture,in which each deflector comprises on the projection-orifice side an edgewhich is curved in such a manner as to approach the shape of saidreceiving surface.
 17. An apparatus according to claim 15, in which apressure screw is arranged between at least one metal sheet and thesupport in order to engage the side of the sheet in the region of thesheet intermediate the support and the projection orifice.
 18. Anapparatus according to claim 14, in which the distance between thedeflectors decreases upon approaching the projection orifice.
 19. Anapparatus according to claim 14, in which said thread guide is aremovable subassembly and in which the cradle is provided with afastening surface which permits the removable fastening of said threadguide to said assembly, the surface being arranged on one of saidbranches on the side opposite one of said deflectors.
 20. An apparatusaccording to claim 19, in which said fastening surface is ofsubstantially smaller dimensions than the length of the deflectorsmeasured along said elongated passage.
 21. An apparatus according toclaim 19, in which said fastening surface is continuous and entirelycircumscribed by a closed line.
 22. An apparatus according to claim 14,in which the thread guide is a unitary subassembly removably mounted tothe apparatus to facilitate removal as a unit and substitution ofanother thread guide.
 23. An apparatus according to claim 14, in whicheach deflector comprises on the projection-orifice side an edge and inwhich the trace which the perpendicular projection of each of said edgesforms in the plane of rotation is non-linear.
 24. An apparatus accordingto claim 14, in which the deflectors are in contact with each other atleast at a point or points in the elongated passage.